linux-kernel - Re: [PATCH v2 15/33] x86/intel_rdt: Adds support to enable Code Data Prioritization

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Message-ID: <alpine.DEB.2.20.1609081215160.5647@nanos>
Date:   Thu, 8 Sep 2016 12:18:59 +0200 (CEST)
From:   Thomas Gleixner <tglx@...utronix.de>
To:     Fenghua Yu <fenghua.yu@...el.com>
cc:     "H. Peter Anvin" <h.peter.anvin@...el.com>,
        Ingo Molnar <mingo@...e.hu>, Tony Luck <tony.luck@...el.com>,
        Peter Zijlstra <peterz@...radead.org>,
        Tejun Heo <tj@...nel.org>, Borislav Petkov <bp@...e.de>,
        Stephane Eranian <eranian@...gle.com>,
        Marcelo Tosatti <mtosatti@...hat.com>,
        David Carrillo-Cisneros <davidcc@...gle.com>,
        Shaohua Li <shli@...com>,
        Ravi V Shankar <ravi.v.shankar@...el.com>,
        Vikas Shivappa <vikas.shivappa@...ux.intel.com>,
        Sai Prakhya <sai.praneeth.prakhya@...el.com>,
        linux-kernel <linux-kernel@...r.kernel.org>, x86 <x86@...nel.org>
Subject: Re: [PATCH v2 15/33] x86/intel_rdt: Adds support to enable Code Data
 Prioritization

On Thu, 8 Sep 2016, Fenghua Yu wrote:
>  
> +struct clos_config {
> +	unsigned long *closmap;
> +	u32 max_closid;
> +	u32 closids_used;
> +};

Another badly formatted and undocumented structure

> +struct clos_config cconfig;
> +bool cdp_enabled;

Once more global variables without a declaration in a header and no user
outside of this file.

> +#define __DCBM_TABLE_INDEX(x)	(x << 1)
> +#define __ICBM_TABLE_INDEX(x)	((x << 1) + 1)
>  
>  struct rdt_remote_data {
>  	int msr;
> @@ -122,22 +123,28 @@ static int closid_alloc(u32 *closid)
>  
>  	lockdep_assert_held(&rdtgroup_mutex);
>  
> -	maxid = boot_cpu_data.x86_cache_max_closid;
> -	id = find_first_zero_bit(closmap, maxid);
> +	maxid = cconfig.max_closid;

Cute. You can remove all that code because maxid is always 0.

>  /*
>   * Set only one cpu in cpumask in all cpus that share the same cache.
>   */
> @@ -191,7 +213,7 @@ static inline bool rdt_cpumask_update(int cpu)
>   */
>  static void cbm_update_msrs(void *dummy)
>  {
> -	int maxid = boot_cpu_data.x86_cache_max_closid;
> +	int maxid = cconfig.max_closid;

Ditto

>  	size = BITS_TO_LONGS(maxid) * sizeof(long);
> -	closmap = kzalloc(size, GFP_KERNEL);
> -	if (!closmap) {
> +	cconfig.closmap = kzalloc(size, GFP_KERNEL);
> +	if (!cconfig.closmap) {

Simply because it's never initialized.

Thanks,

	tglx